1. Field
Example embodiments relate to a maskless exposure apparatus with a plurality of exposure heads.
2. Description of the Related Art
Exposure apparatuses are widely used in a semiconductor or LCD fabrication process. In general, an exposure apparatus exposes a desired pattern on a wafer or a glass substrate using a mask. If the mask is used, problems, such as mask costs and sagging of the substrate due to the large size of the substrate, occur. In order to compensate for these problems, maskless exposure apparatuses using Spatial Light Modulators (SLMs), such as Digital Micromirror Devices (DMDs), are a focus of attention. A maskless exposure apparatus forms a virtual mask through angle adjustment of micromirrors corresponding to a desired pattern by irradiating beams onto SLMs.
In order to achieve exposure of a substrate, the substrate is scanned using a plurality of exposure heads provided with the SLMs mounted thereon. The most important factor in exposure of the substrate is to achieve precise exposure of a desired level at a desired position. If actual positions of the plural exposure heads are different from expected positions, exposure is not achieved at a precise position, and thus exposure quality is greatly lowered.